Neil Young is a smart man and the detailer is absolutely right about water penetrating window seals that leads to door rust, but so doesn’t road salt with spray. Rust never occurs from the outside if the finish remains unbroken. My first SAAB 99 (71) had one of the best engineered bodies for water penetration and drainage and have seen nothing better since. IMO, unibody construction lends itself to easier rust preventative measures then body on frame. In addition to doors,protect the sills, inner/outer fender joints and rear quarters from the inside…the areas of biggest concern which can vary from one make to another. For body on frame trucks, it’s judicious use of “red grease” with a foam brush, painted on to important non heat exposed frame areas. Otherwise, move to area where rust has more trouble taking hold or trade your car before rust “appears”. Once it does, it’s value drops out of sight regardless of mechanical maintenance.